Rob, could you run me through your setup? I'm planning Evohome in our build but the Honeywell planner has been down on their website for a while now? I have no heating in place so will be all new plus underfloor.
I have the following.
Evohome Controller, this acts as my thermostat in the livingroom as well.
Opentherm relay.
6 x TRVs.
I have two radiators in the livingroom, both controlled by the evohome controller instead of the TRVs. You can pick how you want them controlled, you can have them both individual so they will both maintain a temp say 20c. Or you can have one source for the temp which i use the evohome controller, but you can use either TRV also, you can also use individual thermostats and position them where you like.
Its incredibly easy to fit and setup, login then add each device. Then configure the devices and name them. Set a schedule and you have the option of optimising this after a while learns your rooms and will turn on a radiator early so that the temp is achieved by your set time. It will also turn the radiator off early if it learns that the room will hold the heat for a period of time.
The hardest thing with a system like this is getting the whole thing to play nice. I had issues with the boiler locking out.
Turned out it was when all radiators closed down but the boiler was still pumping, the auto-bypass did its job but my boiler didn't like the return temperature being the same as the flow, to fix my issue i had a few options, i went with the easiest and took a TRV of the hall radiator and left it permanently on a small amount so as to reduce the return temp.
Other option was to move the auto-bypass further away from the boiler.
The third option would have allowed me to maintain full control but also have a bypass radiator but would involve routing the auto-bypass through the hall radiator after the TRV on that radiator.
